SAT Question 709e04de: Percentages answer and explanation with Desmos solution

Choice B is correct. It's given that the value of $z$ is $1.13$ times $100$. This can be written as $z=\left(1.13\right)\left(100\right)$, which is equivalent to $z=\left(1+0.13\right)(100)$, or $z=\left(1+\frac{13}{100}\right)\left(100\right)$. It follows that the value of $z$ is $100\%$ of $100$ plus $13\%$ of $100$. Therefore, the value of $z$ is $13\%$ greater than $100$.